Obtain designated physical-chemical properties on compounds submitted by NCI and the examination of selected compounds for in vitro and in vivo efficacy. Obtain the following in vitro data which will be used to evaluate the efficacy of potential radiosensitizing compounds for continued testing within the Drug Development Program: evaluation of sensitization of hypoxic mammalian cells to radiation in vitro; evaluation of lack of sensitization of aerated mammalian cells to radiation in vitro; and evaluation of length of time for toxicity (cell kill) at active levels in in vitro mammalian cell cultures.